In some wells the existing perforations start trailing off on production and the need arises to enhance production from the well with additional perforations into the producing formation at different locations from the original perforations that can then be fractured.
The task of sealing off the old perforations has been undertaken in a variety of ways. They can be straddled with swelling packers as in US 20150053397. Another way is to pump material into the existing perforations such as a controlled electrolytic material also known as CEM into the existing perforations while making new perforations followed by delivering material to the borehole that removes the CEM from the existing perforations. This is illustrated in U.S. Pat. No. 8,857,513. An older technique involved pumping a solidifying material into the existing perforations to seal them and then making new perforations for the continuation of production. This method is illustrated in U.S. Pat. No. 5,273,115.
There are uncertainties in the technique that seeks to plug the existing perforations with a material in that the completeness of the delivery into the perforations cannot easily be determined. Additionally the pressure needed to deliver such materials into the perforations deep enough to get a seat, even if that seal is temporary, can adversely affect subsequent production. Then there are some doubts that all the plugging material has been effectively disintegrated from inside the perforations, which can also impede subsequent production.
The present invention seeks to overcome such uncertainties of prior methods by providing an expandable tubular that can span the perforations in the borehole to facilitate making new perforations and fracturing the new perforations or otherwise performing a treatment operation through the new perforations. The expandable tubular will degrade or disintegrate with time to allow the original well drift diameter to be resumed as well as the original perforations to reopen when production or injection resumes. These and other aspects of the present invention be more readily apparent to those skilled in the art from a review of the detailed description of the preferred embodiment and the associated drawings while recognizing that the full scope of the invention can be determined from the appended claims.
Also relevant in general to the subject of barriers that disappear or degrade are U.S. Pat. Nos. 8,794,335; 8,668,019; 8,297,364; 7,661,481; 7,461,699; 7,451,815; 5,103,911; 3,216,497; 2,261,292; 2,214,226 and 2014/0027127.